I was just riding and my bike felt wobbly and lost air I'm a minute so it wasnt like 5 seconds and all the air came out unlike the other times I've had it. I thought it was a puncture cause I didnt do anything crazy just riding. Anyone know what could be the cause? This is my 2nd flat in 2 months, of riding. Should I patch it up instead of buying a new tube? Also could it be a problem with the quality of the tube?

Seen this many times before. The tube quality is questionable when it splits like that. What we did at the shop was cover the tube with talcum powder.

Punctures on the inner circumference of the tube meant that you immediately checked the corresponding inner surface of the rim, right? Was the rim tape intact? Were there any sharp protrusions or debris there?

Do you actually make that check?

If yes, then why aren't we seeing any of this information in your post? In no, that what is the point of this post? How do you expect people to analyze the state of your rim sight unseen?

When nylon rim tape is too wide for a rim it bends into a U shape and both ends can slash the tube from the inside.

Is the hole in the same location in the tube for both flats?

Yes, my previous 2 flats were pinch, but my last one was similar, two small slits near the valve.

Sorry about that, forgot to post the rim, which has been suspicious since the tape ends where the valve is and that's where the punctures have been

replace the tape & tube.

Replacing the tape is a good move even if it is not related to the problem. Please use Velox or similar cloth rim tape. Tube splits are tough to figure out. Often it is simply poor tube quality. We had a rash of these in 2011 from Specialized. After that batch, the problem went away. Regardless, coat the tube with talc. It does help the tube settle in and not stick to things as well.

what size is the tube and the tire?

reason Im asking is the shop I was using was putting tubes in that were too big (according to a lot on here). The tire is 26X1.50 and the tubes they were using were maybe 1.50-2.5 (approximate)

was getting mucho flats near the valve stem. most on here will say use tubes that are on the smaller side, like maybe 1.0-1.50

The tire is 29x2.10/52-622, the tubes I buy from the LBS is QTubes 29x 1.9-2.3" ISO 50/56-622. Not sure if thats on the bigger side since the tube is a little bit loose on the rim until I add the tire.

A good way to check for burrs or objects is to use a dryer sheet and drag it around the rim, tire, whatever you are checking for snags or protrusions. Dryer sheets will snag on anything and let you know if there's a problem. In agreement with what others have said so far.

Not the puncture pictured, but twin cuts (like an equals sign but with some acute angle) are pinch flats. The tube gets caught, and the two sides each get torn open. Sometimes just one side, and some times both. Both more likely if there is a pinch and you hit something hard.

You can ask the questions without being a dick.

I had a bout with tube quality recently. About half the tubes I bought failed in a similar location.

Those are rim strips, not tape.

Get rid of it and use proper cloth tape.


-Tim-